Abstract: Techniques for fabricating high frequency ultrasound transducers are provided herein. In one embodiment, the fabrication includes depositing a copperclad polyimide film, a layer of epoxy on the copperclad polyimide film, and a polyvinylidene fluoride film on the epoxy. The assembly of materials are then pressed to bond the polyvinylidene fluoride film to the copperclad polyimide film and to form an assembly. The polyvinylidene fluoride film being one surface and the copperclad polyimide film being the other surface. The area behind the copperclad polyimide film surface is filled with a second epoxy, and then cured to form an epoxy plug.

Abstract: Techniques for fabricating high frequency ultrasound transducers are provided herein. In one embodiment, the fabrication includes depositing a copperclad polyimide film, a layer of epoxy on the copperclad polyimide film, and a polyvinylidene fluoride film on the epoxy. The assembly of materials are then pressed to bond the polyvinylidene fluoride film to the copperclad polyimide film and to form an assembly. The polyvinylidene fluoride film being one surface and the copperclad polyimide film being the other surface. The area behind the copperclad polyimide film surface is filled with a second epoxy, and then cured to form an epoxy plug.

Abstract: Techniques for fabricating high frequency ultrasound transducers are provided herein. In one embodiment, the fabrication includes depositing a copperclad polyimide film, a layer of epoxy on the copperclad polyimide film, and a polyvinylidene fluoride film on the epoxy. The assembly of materials are then pressed to bond the polyvinylidene fluoride film to the copperclad polyimide film and to form an assembly. The polyvinylidene fluoride film being one surface and the copperclad polyimide film being the other surface. The area behind the copperclad polyimide film surface is filled with a second epoxy, and then cured to form an epoxy plug.

Abstract: Techniques for fabricating high frequency ultrasound transducers are provided herein. In one embodiment, the fabrication includes depositing a copperclad polyimide film, a layer of epoxy on the copperclad polyimide film, and a polyvinylidene fluoride film on the epoxy. The assembly of materials are then pressed to bond the polyvinylidene fluoride film to the copperclad polyimide film and to form an assembly. The polyvinylidene fluoride film being one surface and the copperclad polyimide film being the other surface. The area behind the copperclad polyimide film surface is filled with a second epoxy, and then cured to form an epoxy plug.

Abstract: Diagnostic ultrasound is used to measure distance from a transducer to selected tissue structure. In one arrangement, the focal point of a high intensity focused ultrasound transducer is adjusted in accordance with measured distance to the selected tissue structure. In a second arrangement a transducer transport apparatus moves a transducer to maintain a selected distance from tissue structure.

Abstract: Diagnostic ultrasound is used to measure distance from a transducer to selected tissue structure. In one arrangement, the focal point of a high intensity focused ultrasound transducer is adjusted in accordance with measured distance to the selected tissue structure. In a second arrangement a transducer transport apparatus moves a transducer to maintain a selected distance from tissue structure.

Abstract: Improved methods of signal processing for generating estimates of tissue strain are presented. These techniques generally employ the frequency shifting of post-compression spectral data to determine a scaling factor which approximates the applied tissue strain. The scaling factor can be determined by finding the maximum correlation between the frequency shifted post-compression data to the pre-compression data and can also be determined by minimizing the variance of the ratio of such data. Correlation tracking and maximum correlation magnitude techniques for improving the results of elastography are also presented.

Abstract: Radiation pulses from a high energy therapeutic ultrasound system are used to stimulate tissue motion by radiation pressure. The tissue motion is monitored using a diagnostic ultrasound system.

Abstract: An apparatus for ultrasonic elastography includes a housing, a moveable surface, and a transducer in ultrasonic communication with the moveable surface. A driver is arranged to mechanically move the moveable surface with respect to the housing. The housing can also be formed such that the moveable surface is a moveable exterior surface of the housing, such as a compliant membrane, which is moved in response to the driver to induce tissue compression. The housing may be arranged to be held in an operator's hand. Alternatively, the housing may be arranged for an insertion into an opening in a patient's body. The driver may move the transducer or moveable exterior surface in a cyclical manner at a low frequency.

Abstract: Abstract of the Disclosure Improved methods of signal processing for generating estimates of tissue strain are presented. These techniques generally employ the frequency shifting of post-compression spectral data to determine a scaling factor which approximates the applied tissue strain. The scaling factor can be determined by finding the maximum correlation between the frequency shifted post-compression data to the pre-compression data and can also be determined by minimizing the variance of the ratio of such data. Correlation tracking and maximum correlation magnitude techniques for improving the results of elastography are also presented.

Abstract: An ultrasound system that enables determination of layer thicknesses and contours of a multi-layer organic body includes a transmitter/receiver for obtaining a radio frequency signal from echoes over a plurality of points on the organic surface. Each radio frequency signal is then deconvolved to remove apparatus generated noise and filtered to create an analytic signal that exhibits a magnitude related to an instantaneous rate of arrival of total echo energy received by the transmitter/receiver. Analytic signals from adjacent parallel scans are then cross-correlated and magnitude detected to determine energy peaks to enable accurate determination of echo producing surfaces of each layer of the multi-layer organic body across the plurality of interrogation points. In the application of the invention to Corneal Epithelium Mapping, a pupil monitoring system is included that disables the measurement system if the pupil's gaze wanders so as to cause a diversion of the optical axis.

Abstract: A method and an apparatus for applying a therapeutic substance to body tissue are provided in which ultrasonic radiation is used. The method allows the application of medication to be tailored to the needs of an individual patient. In particular, the timing, duration, intensity, and concentration of the application of medication can be adjusted according to individual requirements. Side effects of tissue adjacent to tissue in need oThe invention described herein was made in the course of work under a grant from the National Institute of Health.

Abstract: A system is described for obtaining in real-time cross-sectional and 3-dimensional images of a body under study using ultrasonic energy. A piezoelectric transducer is positioned to emit ultrasonic energy and receive echo pulses. The transducer is electronically swept or physically rotated to produce a series of sectored scan planes which are separated by a known angular distance. The echo pulses are processed to produce an ultrasonic image in pseudo 3-dimensional display. By using data from one scan plane, processed as a B-scan image, cross-sectional data can be obtained. Such is combined in a display with an overlay to visually portray the object and positioning information or comparative data. The system is combined with a computer for data analysis and a therapeutic transducer for treatment.

Abstract: Methods for enhancement of data obtained from scanning objects such as body tissue with ultrasonic wideband pulses to detect characteristics of the tissue and to identify the tissue. The methods include performing spectral analysis on selected time portions of signals obtained from ultrasonic scanning to derive spectral data which is representative of the received signal characteristics for spatial samples of a particular region of interest in the body. The characteristic values are selected to correlate with significant characteristics of the material. A display of the selected body region is generated, with the display characteristic for each of the spatial samples being selected in accordance with the derived spectral characteristic values. Examples of the spectral characteristic values include spectral amplitude, spectral slope, and spectral amplitude uncertainty.

Abstract: Methods for improving the availability of information derived from signals received from an object irradiated with coherent pulses of any form of radiation that exhibits a wave nature are disclosed. A method for reducing speckle derives separate component noncoherent signals from the received signals, and combines these separate noncoherent signals to form improved composite noncoherent signals. Weighting and processing of component signals can be applied as a function of time, frequency, and signal amplitude to optimize speckle reduction in all or a critical part of the signal by compensating for the range and frequency dependence of attenuation and the frequency dependence of scattering phenomena. In a method for enhancing resolution, separate component coherent signals are derived from the received signals, weighted and processed, and combined to form improved composite coherent signals; then noncoherent signals are derived from the improved composite coherent signals.

Abstract: An ultrasonic transducer assembly is provided with transducers for both therapeutic and diagnostic ultrasonic radiation. A moveable seal permits adjustment and alignment of the two transducer units in a fluid medium. In addition, there is provided a light beam directed along the axis of the ultrasonic radiation. The transducer assembly is particularly useful for ophthalmic therapy.

Abstract: An ultrasonic wave transducer is formed from a body of piezoelectric material having nonuniform thickness. Each location on the transducer is resonant at a different frequency according to the thickness at that point. By changing the frequency of the applied excitation signal, the origin and direction of the radiation can be altered.

Abstract: Methods for improving the availability of information derived from signals received from an object irradiated with coherent pulses of any form of radiation that exhibits a wave nature are disclosed. A method for reducing speckle derives separate component noncoherent signals from the received signals, and combines these separate noncoherent signals to form improved composite noncoherent signals. Weighting and processing of component signals can be applied as a function of time, frequency, and signal amplitude to optimize speckle reduction in all or a critical part of the signal by compensating for the range and frequency dependence of attenuation and the frequency dependence of scattering phenomena. In a method for enhancing resolution, separate component coherent signals are derived from the received signals, weighted and processed, and combined to form improved composite coherent signals; then noncoherent signals are derived from the improved composite coherent signals.